A brushless direct current (BLDC) motor may prevent friction and wear which are disadvantages of the existing DC motor and have relatively high efficiency. Therefore, recently, hybrid cars tend to adopt the BLDC motor as a motor for rotating a cooling fan.
The BLDC motor is a motor that does not have a brush and a commutator necessary for a DC motor but has an electronic commutation mechanism installed therein.
Further, the existing BLDC motor assembly for a low-voltage cooling fan for a vehicle has a motor unit and an inverter unit that are formed integrally, and thus is configured of an inverter built-in BLDC motor. Here, as illustrated in FIG. 1, an inverter housing 21 is coupled to a lower side of the motor unit 10, a cover 22 is coupled to a lower side of the inverter housing 21, and a PCB substrate is provided in an internal space formed by the inverter housing 21 and the cover 22, such that the inverter unit 20 is formed. Further, one side of the inverter unit 20 is provided with a connector block assembling part 23 for connecting an internal PCB substrate and an external inverter control unit to each other by a power supply line and a communication line, and a connector block assembling part 23 is provided with a through hole 24 for connecting between an inside and an outside thereof. Further, the connector block 30 is provided with a communicating tube 31 protruding from one surface thereof and thus is fastened to the connector block assembling part 23 by a fastener or the like so that the communicating tube 31 is inserted into the through hole 24. At this point, the communicating tube 31 is inserted into a through hole 24 in a state where a connector sealing rubber 40 such as an O-ring is inserted into an outer side of the communicating tube 31, such that a space between the communicating tube 31 and the through hole 24 is sealed. Further, the electric wires is connected to the PCB substrate in the inverter unit 20 through the communicating tube 31 and the through hole 24 and the sealing rubber such as wire sealing is used to seal between the electric wires and an inner circumferential surface of the communicating tube 31.
That is, since the existing inverter built-in BLDC motor uses several sealing rubbers for water tightness between the inverter unit 20 and the connector block 30 and water tightness between the connector block 30 and the electric wires, a structure of a connector block package including the connector block, the sealing rubber or the like is complicated, such that a process of producing and assembling parts may be complicated and manufacturing costs may be increased.